If Brendan Rodgers was little more clipped than normal as he sat down at Lennoxtown to oversee tonight’s UEFA Champions League qualifier against Rosenborg, there is an acceptance of why his mood has been coloured by recent events.

Denied an experienced defender with last week’s red-card for Jozo Simunovic – and therefore forced to revisit what now appears to be a perennial transfer window centre-half question – Rodgers does not have a straightforward decision to make in terms of his team selection tonight.

The rarely sighted Marvin Compper is out while Dedryck Boyata continues to holiday after a break from his World Cup exertions. Mikael Lustig has just returned from his campaign with Sweden while Moussa Dembele’s hamstring will keep him out of this tie altogether.

Read more: Celtic manager Brendan Rodgers insists Dedryck Boyata won't leave before Champions League qualifiers

And Rodgers was scathing of the idea that having ready made replacements to offset the scenario Celtic are in is easy to manipulate.

“The problem is that if you are going to bring in a top, top centre-half then that is going to cost you money,” he said. “It is as simple as that. And big money. That is out of my control. If not then you have to do what the club has always done. You bring in players who fit the model of the club and you develop them and improve them and then probably eventually they move on. Somewhere along the line you’ll need that level of experience to come in and try and support and then you hope that can work out for you.

“It is probably easier to write or to say that if you lose a centre-half you should have another one. I think people expect you to have ten centre-halves. Football doesn’t work like that in the real world. It might do on the computer games but it doesn’t work like that. You have got to build a squad but if you bring people in and they get injuries then it is a challenge. You can’t moan about it. You just need to get on with it as best you can.”

In terms of immediacy, it is a pressing headache. On the long-term, however, there is the constant background music that accompanies every transfer window.

Read more: Was Rosenborg coach Rino Coolen having us on or does he really not know anything about Celtic?​

Rodgers has been the most expensive manager ever to have been employed by Celtic. But for the handsome salary that Rodgers banks for his day job, he has repaid it significantly; Celtic have reaped in excess of £60m for their last two successive Champions League campaigns, there have been back-to-back trebles celebrated by the club, there was a £7.5m windfall this January when Virgil van Dijk made the switch move from Southampton to Liverpool and then there was a £7m fee banked for Stuart Armstrong last month.

That has been offset by a club record transfer for Odsonne Edouard but as of yet further signings have yet to follow. There have been three bids placed for Hibs midfielder John McGinn, all of which have been knocked back by the Leith club who value the player at £4m.

From the club’s point of view and in a broader sense, it is not necessarily transfer fees that prove prohibitive but rather salary levels with inflated amounts south of the border impinging on the kind of market they can operate in.

It was difficult, though, not to read an element of frustration into Rodgers as he sat on the fence when asked if he anticipated being in a stronger position at the end of the window than he is now. “I’m not sure, I’m not sure,” he stated.

“I’ll work with the players that’s here, the players that we have, and then obviously what the club can do, they will do.

​Read more: Celtic manager Brendan Rodgers insists Dedryck Boyata won't leave before Champions League qualifiers​

“The club works in a specific way. You don’t need to be a rocket scientist to know that if you are going to improve drastically from what this group is at and where it has got to over the last couple of years that in order for that to make the improvements that people want to make, it costs money. But that is out of my control.”

While those questions will hang around until the window closes, Rodgers’ main focus is on guiding Celtic back into the group stages of the Champions League.

The next step on that journey comes tonight and the Celtic manager is wary of anticipating the crisis at Rosenborg as having an impact on the pitch.

“It can go both ways, can’t it?,” said Rodgers.

“It can galvanise the players where they come together and become stronger. Or there is a negative impact with it all.

“But for us we can only concentrate on ourselves. The previous manager had done a great job over his time there and looks unfortunate to have lost his job.

Read more: Was Rosenborg coach Rino Coolen having us on or does he really not know anything about Celtic?​

“Their players and supporters have made that clear.

“But Rosenborg are a very famous club with a big tradition in Norway and European football so I’m sure they’ll come together and look to be a problem for us.

“I think it is unfair that we have to play four rounds. It is tough with three so to have the extra one in is a little unfair on the likes of ourselves who have been the sole representatives in European football. It has been organised to help the big leagues and we just have to deal with that but we have to deal with it.”